The present disclosure relates to an amplifier, a liquid crystal displaying driving circuit and a liquid crystal display apparatus.
As display apparatus, the liquid crystal display apparatus (LDC: Liquid Crystal Device) is widely spread. In the liquid crystal display section of a liquid crystal display apparatus, a plurality of pixels configured from transistors, diodes and so forth are provided. The pixels are driven by a liquid crystal displaying driving circuit to display an image on the liquid crystal display section. The liquid crystal displaying driving circuit includes a plurality of amplifiers, and a driving signal amplified by each amplifier is supplied to the pixels for each line to drive the pixels.
In recent years, liquid crystal display apparatus are demanded to have a larger screen and higher definition, and also desired to have reduced power consumption. Advancement of screen size increasing and definition enhancement of liquid crystal display apparatus increases the power consumed by amplifiers provided for the lines in the liquid crystal display section. In order to implement low power consumption of liquid crystal display apparatus, it is important to reduce the power consumption of amplifiers in the liquid crystal displaying driving circuit. However, there is a problem that, if the power consumption of the amplifiers of the liquid crystal displaying driving circuit is reduced, then the slew rate of the amplifiers drops.
Japanese Patent Laid-Open No. 2001-156559 discloses, as a method of increasing the slew rate of amplifiers while suppressing their power consumption, a method in which the steady-state current of amplifiers is increased or decreased in response to the increase or decrease in the output potential of the amplifiers. Such an amplifier as disclosed in the document mentioned above includes a steady-state current source and a sub current source for generating current in response to the increase or decrease in the output potential of the amplifier. The steady-state current supplied from the steady-state current source is reduced, and upon rise and fall of an input signal, the sub current source supplies a steady-state current so that the slew rate of the amplifiers can be increased while suppressing the power consumption.